YANGON (Reuters) - Myanmar police have charged five journalists with "disclosing state secrets" after their newspaper carried a story about an alleged chemical weapons factory, state media reported Sunday.

The trial of four reporters and the head of Unity Journal began on February 14 in Pakokku, a town in the country's central region where the military facility is located, the state-run New Light of Myanmar newspaper said.

The New Light of Myanmar said charges under the Official Secrets Act also included "trespassing on the restricted area of the factory", but the newspaper did not disclose the nature of the facility.

Government spokesman Ye Htut told local media last week that the factory did not produce chemical weapons. He could not be reached for comment on Sunday.

The Committee to Protect Journalists (CPJ) on February 3 called for the suspects' release, saying "journalists should not be threatened or arrested for reporting on topics of national and international importance".

The Unity Journal story claimed the secret facility built in 2009 consisted of tunnels burrowed under 3,000 acres of land and quoted workers as saying the factory produced chemical weapons, according to the CPJ, which noted reports that authorities confiscated copies of the publication.

Myanmar's former junta, which handed power to a quasi-civilian government in 2011, has repeatedly denied accusations that it used chemical weapons against ethnic insurgent groups.

In 2005, British-based rights group Christian Solidarity Worldwide said it interviewed five ethnic Karen rebels who suffered symptoms consistent with a chemical weapons attack, as well as two government soldiers who defected after the alleged attack took place. The soldiers told the rights group the use of chemical weapons was widespread, and one said he was ordered to carry boxes of chemical weapons to the front line.

Ahmet Uzumcu, head of the Nobel Peace Prize-winning Organisation for the Prohibition of Chemical Weapons, said in December that Myanmar was preparing to join the convention banning chemical weapons.

(Reporting By Jared Ferrie; Editing by Jeremy Laurence)

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